‘Titanic Too’ – a rebreather breakthrough

A CDBA semi-closed circuit rebreather set formerly in use with the RN and RAN.

Once again proving that the only barriers that exist in diving are the self-imposed limitations of logical thought, the Zymurgy Inc. R&D team have developed their own Semi-Closed Circuit Rebreather, the ‘Titanic Too’.

Appreciating that unit cost has been a major factor affecting the widespread introduction of rebreather technology, the design team set out to produce an inexpensive model peculiarly suited to the Australian and New Zealand markets

With minor modifications, but employing a system common to all rebreathers, the ‘Titanic Too’features a gas supply, counter-lung, gas-flow regulator, breathing hoses and a scrubber mechanism to remove carbon dioxide from the exhaled gas. “But it’s in the choice of materials and the operational mechanics that the ‘Titanic Too’ differs from other more conventional rebreathers.” Said Zymurgy Inc’s international Marketing Director, David Strike.

“We gave considerable thought to the selection of a suitable counter-lung (or breathing bag),” said David Strike, founder of Zymurgy Inc., “one that was inexpensive, easy to obtain and which lent itself to field maintenance. After considerable testing we finally settled on a 6-litre bladder from a cask wine produced by an obscure West Australian vineyard.

“Quite an acceptable drop, as I recall. Although the hint of strawberry on the middle palate was rather overshadowed by the wine’s somewhat astringent qualities.

“During a normal rebreather cycle”, Strike continued, “the exhaled gas passes through a chemical scrubber that removes carbon-dioxide. This usually consists of either soda lime pellets or the more expensive lithium hydroxide, neither of which are readily available from your neighbourhood supermarket.

“This fact caused us to consider more revolutionary methods.” He added. “You could say that we found inspiration in the sea itself. Water can, when in its gaseous form – steam – be used to power the engines of mighty vessels like the ‘RMS Titanic’; the same water which, when in its solid state – ice – can also cause catastrophe.. We therefore determined to perfect a cryogenic system that would fill a dual role. One: To keep the drinks cool. Two: To act as an efficient CO2 scrubber.”

During the exhalation cycle of the ‘Titanic Too’ system, the movement of the gas causes minute fibres embedded along the inner surface of the exhaust hose to vibrate. These vibrations are harnessed to produce electricity that in turn activates a small, but powerful, pump located on the down-stream side of the hose’s non-return valve.

Driving a compressor that pumps an ultra-refrigerant through a sealed unit of metal coils – in a process not dissimilar to that of the domestic refrigerator – the CO2 rich exhaust gas passes across the series of narrow bore metal coils into a rigid reservoir canister containing a large block of ice: a denser gas than oxygen the CO2, on contact with the ice, forms into molecular droplets which gather on the bottom of the canister while the oxygen is allowed to pass through a porous membrane back into the loop.

While early field trials of the, ‘Titanic Too’, have revealed minor flaws in the unit’s operational duration – mainly to do with rapid melting of the ice in tropical waters, and the need to constantly surface and drain the canister – the manufacturers’ claim that this will prove nothing more than a minor inconvenience to the intended market of thinking/drinking divers.

“Based on feedback from those divers privileged to test dive the prototype unit, it’s tempting to say that the ‘Titanic Too’is proving to be an unsinkable success.” Said Strike, “Sadly, however, we are still experiencing minor set-backs in countering the unit’s negative buoyancy characteristics. Problems that will, undoubtedly, be resolved before the unit makes its debut in a liquor store near you sometime before the year 2015 .”